This microscope image (400x magnification) shows an oval cluster of roughly 1,000 human embryonic stem cells growing together as a colony. This colony is part of the UM4-6 human embryonic stem cell line created by the University of Michigan Consortium for Stem Cell Therapies. Image courtesy of Gary Smith.

Magnified image of a human blastocyst. Green area is the inner cell mass, the cluster of cells along the inner wall of the blastocyst that provide the embryonic stem cells. The red cells are trophectoderm. Photo courtesy of Gary Smith, University of Michigan.

Differentiated human embryonic stem cells, known as embryoid bodies. Embryoid bodies are spherical colonies of embryonic stem cells, seen only in culture and containing all three germ layers: endoderm, mesoderm and ectoderm. Photo courtesy of Gary Smith, University of Michigan.

A magnified image (200x) of a thousands of human embryonic stem cells growing together as a colony (the silver cluster of cells in the center of the image) growing on top of mouse feeder cells (the dark filamentous structures). These cells can become any cell type in the body and divide indefinitely. Courtesy of Jack Mosher, PhD.

High magnification image of human embryonic stem cells differentiated into neurons (red cells) by treating cells with a growth factor. These could be used to study the development of the nervous system, birth defects or to replace cells lost to injury, aging or diseases such as Parkinson’s. Courtesy of Sue O'Shea, PhD